Another concept is the exploration of different timelines within the crossover. Maybe there's a timeline where Shirou makes different choices due to the influence of the crossover elements. This can lead to a whole new set of battles and relationships. Also, the combination of different magic systems from the crossovers can create really cool and unexpected effects in the story.
One Piece's Luffy is also quite popular. His carefree and determined personality contrasts with the more serious tone of Unlimited Blade Works at times. His devil fruit powers can introduce some really wacky and interesting elements into the story. Additionally, characters like Goku from Dragon Ball Z are frequently used in crossovers. His super - strong fighting abilities and Saiyan heritage can lead to epic battles against the Servants in the Unlimited Blade Works world.
A common concept is a power - up or alternate power - set for both characters in the crossover. Shirou might gain some of Kotomine's knowledge of the Grail or his combat skills, while Kotomine could inherit Shirou's ability to project weapons in a new and unexpected way. This could change the power dynamics in battles and the overall plot of the fanfiction.
Well, a cool 'unlimited blade works crossover fanfiction' idea might involve crossing it with a sci - fi setting. For example, Shirou finds himself on a spaceship and has to use Unlimited Blade Works against alien threats. It could also be interesting to cross it with a historical - fiction world, like the samurai - era Japan. He could have duels with famous samurai using his blade - creating ability. And then there's the idea of crossing it with a magical girl universe. His serious and practical magic would be an interesting contrast to the more flamboyant magic of magical girls.
One interesting concept could be the exploration of Shirou's character in a different servant - like form. It might show new powers or abilities that are not seen in the original story. For example, his combat style could be enhanced or altered in unique ways.
One interesting concept could be the unique interpretations of Shirou's power. In some fanfictions, his Reality Marble might be expanded or modified in ways that show new aspects of his character. For example, it could be used to explore his deepest desires or fears more thoroughly than in the original work.
One interesting concept could be new spells created by fans. For example, a spell that allows the caster to temporarily become invisible without the use of the Invisibility Cloak. This can add a new dimension to the magical world in the fanfiction.
One idea could be Izuku discovers he has the ability to use Unlimited Blade Works in a moment of extreme danger. He starts training with it secretly, trying to master the different blades and their unique powers.
Well, there could be a fanfiction where the OC user is a time - traveler who enters the Unlimited Blade Works. This OC might try to change certain events in the story. They could interact with the existing characters in unexpected ways, like teaching Archer a new combat technique that he then incorporates into his fighting style, which in turn affects the overall battles and relationships in the Unlimited Blade Works world.
Well, Shirou in crossover fanfiction often shows his tenacity. No matter how strange or difficult the new world he is in, he doesn't give up easily. In a crossover with the Digimon world, he faces many challenges but keeps fighting. His loyalty is also a big part of his character. If he makes friends in the new world, he will be loyal to them and protect them at all costs. And his growth as a character is interesting. He may start with his basic set of skills from his original world, but as he experiences new things in the crossover world, he evolves, both in terms of his combat abilities and his understanding of different cultures and values.
One interesting concept could be Shreck crossing over with other fairytale characters in a modern setting. For example, Shreck meeting characters from 'Cinderella' in a bustling city. It can create humorous and unexpected interactions, like Shreck's gruff nature clashing with Cinderella's elegance.